Treatment strategies for patients with a high risk of and with a heart attack

This fact box will help you to weigh the benefits and harms of two treatment strategies for patients at high risk of and with a heart attack. The information and numbers are based on the best scientific evidence currently available.

This fact box was developed by the Harding Center for Risk Literacy.

What is angina pectoris?

Risk of a heart attack increases when the blood vessels that carry blood to the heart (coronary blood vessels, coronary arteries) are narrowed. This condition is called coronary heart disease (CHD). One symptom of CHD is angina pectoris, where chest pain and a sensation of pressure on the chest can occur either due to physical exertion (stable angina) or independent of it (unstable angina).

The pain is caused by a narrowing of the coronary arteries. Part of the heart is no longer sufficiently supplied with blood, which leads to the heart muscle being deprived of oxygen. If these arteries are blocked entirely, a heart attack occurs. The risk of a heart attack is high for patients with unstable angina. However, the symptoms of an unstable angina cannot be distinguished from those of a heart attack.

People whose chest pain is continuous or recurrent may haveunstable angina or a type of heart attack that is known as non-ST elevation myocardial infarction (NSTEMI) [1].

What is a non-ST elevation myocardial infarction?

If a heart attack is suspected (chest pain with a feeling of tightness, difficulties breathing, or other symptoms), an electrocardiography (ECG) will be performed. The electrocardiography enables a heart attack with ST elevation (STEMI) to be distinguished from a heart attack without ST elevation (NSTEMI). If it is an STEMI, there is a change in the ECG pattern that shows an elevation of the ST segment. This does not occur if it is an NSTEMI.

Determining the type of heart attack that occurred is relevant for classifying its severity and deciding on further treatment [1].

What are the treatment strategies for angina pectoris and non-ST elevation myocardial infarction?

Two strategies to treat these two conditions exist: direct invasive treatment or initial drug therapy (conservative strategy). Invasivemeans that the diagnostic and treatment procedures enter (invade) the body.

Direct invasive treatmententails the following: All patients receive a coronary angiography shortly after hospitalization. In this procedure, a catheter (long, hollow tube) is inserted into the coronary arteries to detect thickenings and hardenings. If abnormalities are found, a balloon catheter can be used to dilate the artery in order to improve blood flow to the heart muscle. A metallic stent can be used to keep the artery open. If the area of the artery in question cannot be reached by this procedure, a surgical bypass might be necessary, in which blood flow is redirected to bypass the blockage.

Initial drug therapy(conservative strategy) uses medication at first. However, if patients continue to suffer from chest pain or if tests such as stress testing or imaging show signs of further narrowing of the arteries, a coronary angiography and the corresponding procedures (stent or bypass) might be performed [1].

Who might consider these treatment strategies?

These strategies target people who suffer from unstable angina or a heart attack without ST elevation [1].

Fact box treatment strategies for patients with a high risk of and with a heart attack
Fact box treatment strategies for patients with a high risk of and with a heart attack © Harding Center for Risk Literacy
What does the fact box show?

This fact box shows the benefits and harms of initial drug therapy compared to direct invasive treatment for patients.

The table may be read as follows:

8 out of every 100 patients, monitored for 6 to 12 months, who were treated with initial drug therapy had a heart attack. Of every 100 patients who received direct invasive treatment, 6 had a heart attack.

The numbers in this fact box are rounded. The data are based on 8 studies with about 9,000 participants [1].

What other aspects should be considered?

This fact box is based solely on studies in which stents were implanted. Current clinical practice uses stents that partly differ from those in the studies included here. For example, in addition to metallic stents, drug-eluting stents are now available [1].

Do the results provide proof (evidence) for the benefits and harms of the treatment strategies?

Overall, the evidence is of low to moderate quality: Further research is likely to affect some findings (where evidence is of moderate quality) and very likely to affect the findings of mortality (where evidence is of low quality).

Version history of the fact box
  • March 2017 (last update)
Sources

Information within the fact box was obtained from the following source:

[1] Fanning JP, Nyong J, Scott IA, et al. Routine invasive strategies versus selective invasive strategies for unstable angina and non-ST elevation myocardial infarction in the stent era. Cochrane Database Syst Rev 2016(5):CD004815. doi: 10.1002/14651858.CD004815.pub4

Documentation on how the numbers in the fact box were determined is available on request.